Cleaning implement based on melamine-formaldehyde foam comprising hollow microspheres

ABSTRACT

The present invention relates to a cleaning implement based on melamine-formaldehyde foam comprising hollow microspheres, wherein said hollow microspheres have a median particle diameter (D 50 , volume averaged, Malvern, Fraunhofer diffraction) in the range from 260 μm to 490 μm, and wherein the hollow microsphere are at least partly filled with a benefit agent. Additionally the present invention encompasses a method for cleaning a hard surface with a cleaning implement according to the present invention.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/486,414, filed May 16, 2011, the substance of which is incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to cleaning implement based onmelamine-formaldehyde foams comprising hollow microspheres.

BACKGROUND OF THE INVENTION

Recently, a novel application for such melamine-formaldehyde foams inthe area of hard surface cleaning has been discovered. Indeed, cleaningimplements of cut or molded pieces of such melamine-formaldehyde foam,and in particular melamine foam, have become popular to remove soilsand/or stains from hard surfaces (i.e., cleaning of hard surfaces) suchas tiles, walls, floors, sanitary fittings such as sinks, showers,shower curtains, wash basins, WCs, household appliances including, butnot limited to, refrigerators, freezers, washing machines, automaticdryers, ovens, microwave ovens, dishwashers and so on. Indeed, melaminefoam sponges are currently marketed under the tradename Mr. Clean MagicEraser®.

It is has been observed that melamine-formaldehyde foam in particularshows good soil and/or stain removal performance when used to clean hardsurfaces, on stains/soils such as marks on walls and furniture. Indeed,it has been observed that melamine foam in particular, when wetted withan appropriate solvent, such as tap water, removes soils and/or stainsfrom a hard surface when said hard surface is brought into contactedwith said wetted modified open-cell foam. By “bringing into contact” itis meant wiping, swiping, rubbing or the like. In order for the melaminefoam in particular to optimally remove soils and/or stains from hardsurfaces substantial amounts of an appropriate solvent, such as tapwater, have to be used. Most commonly, tap water is used by the users ofmelamine foam when removing soils and/or stains from hard surfaces. Whenused with water or any other appropriate solvent, the melamine foam inparticular comes off as small particles (meaning, the foam crumbles)when brought into contact with a hard surface. Indeed, a milkysuspension of small modified melamine foam in particular particles inwater is formed. However there has been the need for better soil and/orstain removal with better durability upon use.

It is therefore, an objective of the present invention to provide acleaning implement, wherein said implement is capable of (improved)cleaning greasy soap scum soils and neat kitchen dirt (grease) from hardsurfaces whilst providing a good surface safety profile and at the sametime showing excellent durability upon use.

It has been now found that above objective can be met by use of cleaningimplement based on melamine-formaldehyde foams comprising hollowmicrospheres, wherein said hollow microspheres have a median particlediameter (D₅₀, volume averaged, Malvern, Fraunhofer diffraction) in therange from 260 μm to 490 μm and wherein the hollow microspheres are atleast partly filled with a benefit agent. Indeed, the objectives are metby cleaning implement according to present invention based on suchmelamine-formaldehyde foam, the method of cleaning hard surfaces withsuch a cleaning implement or the method of cleaning hard surfaces withthe melamine-formaldehyde foams according to present invention.

The melamine-formaldehyde foams of the present invention have goodmechanical foam properties and better fixation of the hollowmicrospheres in the foam particularly at high loadings, i.e., hollowmicrosphere contents and any associated benefit agent. Furthermore, thehollow microspheres can be incorporated in the foam in the course offoam production without additional process step.

The articles, processes and uses according to the present invention willnow be described.

SUMMARY OF THE INVENTION

The present invention relates to a cleaning implement (1) based onmelamine-formaldehyde foam comprising hollow microspheres (5), whereinsaid hollow microspheres have a median particle diameter (D₅₀, volumeaveraged, Malvern, Fraunhofer diffraction) in the range from 260 μm to490 μm, and wherein the hollow microspheres are at least partly filledwith a benefit agent.

The present invention further encompasses a method for cleaning a hardsurface with a cleaning implement according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cleaning implement (1).

FIG. 2 is a perspective view of a cleaning implement (1) comprising twolayers.

DETAILED DESCRIPTION OF THE INVENTION Cleaning Implement

The cleaning implement (1) herein is based on the melamine-formaldehydefoam comprising hollow microspheres (5), wherein the hollow microspheres(5) are at least partly filled with benefit agent.

By a “cleaning implement” it is meant herein an article of manufactureof any suitable shape and/or size and/or volume suitable for cleaning,i.e., removing spots and/or stains from hard surfaces. In a highlypreferred embodiment according to the present invention, the cleaningimplement herein is in a shape and/or size and/or volume suitable foruse by a consumer to clean hard surfaces therewith. Examples of cleaningimplements are wipers, brushes, cleaning cloths or cleaning granules.

In a preferred embodiment, the cleaning implements herein are suitablefor cleaning/cleansing inanimate surfaces selected from the groupconsisting of household hard surfaces; dish surfaces; surfaces likeleather or synthetic leather; and automotive vehicles surfaces.

In a highly preferred embodiment, the cleaning implements herein aresuitable to clean household hard surfaces.

By “household hard surface”, it is meant herein any kind of surfacetypically found in and around houses like kitchens, bathrooms, e.g.,floors, walls, tiles, windows, cupboards, sinks, showers, showerplastified curtains, wash basins, WCs, fixtures and fittings and thelike made of different materials like ceramic, vinyl, no-wax vinyl,linoleum, melamine, glass, Inox®, Formica®, any plastics, plastifiedwood, metal or any painted or varnished or sealed surface and the like.Household hard surfaces also include household appliances including, butnot limited to refrigerators, freezers, washing machines, automaticdryers, ovens, microwave ovens, dishwashers and so on. Such hardsurfaces may be found both in private households as well as incommercial, institutional and industrial environments.

Suitable shapes of the cleaning implements (1), such as a wiper, hereinmay be selected from the group consisting of: cube shape, rectangularshape, pyramid shape, cylindrical shape, cone shape, pencil erasershape, cuboid shape, tetrahedron shape; sphere shape; globular shape;and ellipsoid shape. Preferably, said cleaning implement has a shapeselected from the group consisting of: cube shape, rectangular shape,pencil eraser shape, and cuboid shape.

Suitable volumes of the cleaning implements herein may be from 1 cm³ to10,000 cm³, preferably from 10 cm³ to 1,000 cm³, more preferably from150 cm³ to 250 cm³.

In a highly preferred embodiment herein, the cleaning implement (1)herein has a cuboid shape defined by three groups of parallel and equallength sides, referred to as a, b and c, wherein a ranges from 2 cm to20 cm, preferably 4 cm to 8 cm, b ranges from 2 cm to 20 cm preferably 8cm to 15 cm, and c ranges from 1.5 cm to 5 cm, preferably 2 cm to 4 cm.

In a preferred embodiment according to present invention, the thicknessof said melamine-formaldehyde foam comprising hollow microspheres foam(2) layer is from 5 mm to 100 mm, preferably from 7 mm to 50 mm, morepreferably 10 mm to 50 mm even more preferably from 15 mm to 50 mm,still more preferably from 20 mm to 40 mm.

The cleaning implement (1) of a first embodiment of the presentinvention as shown in FIG. 1 comprises a single layer (2) ofmelamine-formaldehyde foam comprising hollow microspheres (5).

In a preferred embodiment according to the present invention thecleaning implements herein may comprise additional layers of material.Preferably, in the cleaning implement herein said melamine-formaldehydefoam (2) comprising hollow microspheres (5) forms a first layer and saidcleaning implement additionally comprises a second layer of material.Even more preferably, said second layer of material is a second foamlayer (3) made of a second foam material as discussed herein below. Sucha cleaning implement according to this preferred embodiment is shown inFIG. 2.

The layers of melamine-formaldehyde foam (2) comprising hollowmicrospheres (5) and second foam (3) may be arranged in said cleaningimplement in any way suitable. In a preferred embodiment according topresent invention the layers of melamine-formaldehyde foam (2)comprising hollow microspheres (5) and second foam (3) are arrangedparallel to at least one side, preferably two opposite sides, of thecleaning implement. However, the cleaning implement may also have anirregular shape. Indeed, the thickness of the layers may be constant orvary throughout the cleaning implement. The separation line (4) betweenthe two layers may form a straight line or may form a bend or becompletely irregular. In addition, the separation plane of the layersmay be in the center of cleaning implement, dividing the implement intwo equal parts, or may be in the upper or lower part of the implement.In addition, the cleaning implement may be in the shape of a sphere or aglobule or an ellipsoid with the separation plane of the layers forminga spherical segment or one of the layers, preferably the layer of asecond foam here, forming a sphere in a sphere (similar to the layers ofan onion).

In this highly preferred embodiment of the present invention, whereinthe cleaning implement (1) herein has a cuboid shape, the lineindicating the separation (4) of the two layers (or the surface areaswhere the two layers are joined together) of the implement is preferablysubstantially parallel (preferably parallel) to the side of the cuboidshaped implement having the largest surface area (as shown in FIG. 2).

In another highly preferred embodiment herein the cleaning implementherein is in the shape of a pencil eraser. By “shape of a pencil eraser”it is meant herein a voluminous body having six walls, wherein threepairs of parallel and equally shaped and sized walls exist and whereinone pair of walls are in the shape of a parallelogram and the remainingtwo pairs of walls are of rectangular shape. In this preferredembodiment, wherein the cleaning implement herein has the shape of apencil eraser, the line indicating the separation of the two layers (orthe surface areas where the two layers are joined together) of theimplement is preferably substantially parallel (preferably parallel) tothe side of implement in the shape of a pencil eraser having the largestsurface area.

In order to obtain suitable cleaning implements according to a preferredembodiment of the present invention, the melamine-formaldehyde foamlayer (2) comprising hollow microspheres (5) and the second layer ofsecond foam (3) have to be attached to each other. This attachment canbe achieved by any attachment means suitable for joining the two layers.The attachment may be either a permanent attachment (wherein the twolayers cannot be separated without inflicting substantial damage to thelayers) or temporary attachment (wherein the two layers may be separatedwithout inflicting substantial damage to the layers). Suitableattachment means providing a permanent attachment are selected from thegroup consisting of: foam flame laminating the two layers together; useof a permanent adhesive; sewing the two layers together; andneedle-punching the two layers together; and combinations thereof.Suitable attachment means providing a temporary attachment are selectedfrom the group consisting of: a weak adhesive; Velcro; and awater-based, water-soluble coating or adhesive; and combinationsthereof.

In a preferred embodiment here, the attachment of layers herein is apermanent attachment.

Foam flame lamination is a continuous process that can adhere foams andadditional materials, if any, to one or both sides of foam in a singlepass. The process of flame lamination involves the passing of first foam(either the melamine-formaldehyde foam comprising hollow microspheresherein or the second foam herein) over an open flame, which creates athin layer of molten foam/polymer. Second foam (either the second foamherein or the melamine-formaldehyde foam comprising hollow microspheresherein, depending on the first step) is pressed against the first foamwhile it is still in the molten state. Foams and additional material, ifany, can be adhered to one or both sides of the foam in a single pass.Furthermore, additional passes are optional. The strength of the bonddepends upon the foams and additional material, if any, selected and theprocessing conditions (i.e., gas type, flame height and spread, foamburn-off and nip pressure).

The cleaning implement according to the present invention may containmore than two layers, wherein said additional layers, if, any, may be ofthe same or similar materials as the melamine-formaldehyde foamcomprising hollow microspheres or said second foam, or may be made ofanother material having similar properties as said second foam ordifferent properties therefore. Indeed, the cleaning implement hereinmay be in a so-called sandwich configuration, wherein three layers arepresent. In a preferred embodiment, wherein the cleaning implementherein is in a sandwich configuration, the middle layer may be saidsecond foam and at least one of the two outer layers ismelamine-formaldehyde foam comprising hollow microspheres with thesecond outer layer being either melamine-formaldehyde foam comprisinghollow microspheres or another material providing other feature, such asabrasiveness or increased rigidity. In a highly preferred embodimentaccording to the present invention the cleaning implement hereincomprises two outer layers of said melamine-formaldehyde foam comprisinghollow microspheres and an inner layer, preferably of a second foammaterial, as discussed herein below.

The layers of the cleaning implement according to the present inventionmay cover each other either partially or fully. By a “partial coverage”it is meant that at least one of the layers overlaps the other layer (orother layers, if any) and is not fully covered by said other layer (orother layers, if any). By a “full coverage” it is meant that the layersof the cleaning implement do fully cover each other and that none of thelayers substantially overlap the other layer (or other layers, if any).

The ratio of said melamine-formaldehyde foam comprising hollowmicrospheres to said second foam in the cleaning implement according tothe present invention is preferably from 20:1 to 1:20 by volume, morepreferable from 10:1 to 1:10 by volume, even more preferably 5:1 to 1:1,still more preferably 5:1 to 2:1, and most preferably from 4:1 to 3:1 byvolume.

In order to obtain suitable cleaning implements according to the presentinvention, the melamine-formaldehyde foam comprising hollowmicrospheres—and second foam-raw materials may have to be modified inshape and/or size. This modification can be done by any means known tothose skilled in the art. Suitable means of modifying the shape and/orsize of melamine foam- and second foam-raw materials may be selectedfrom the group consisting of: cutting, breaking, and tearing, andcombinations thereof.

Melamine-formaldehyde foams as such and their production and also hollowmicrospheres as such and their production are known to a person skilledin the art and described in the literature.

The melamine-formaldehyde foams of the present invention comprise hollowmicrospheres and these hollow microspheres in accordance with anessential requirement have a median particle diameter (D₅₀, volumeaveraged, Malvern, Fraunhofer diffraction) in the range from 260 μm to490 μm, preferably in the range from 280 μm to 450 μm and morepreferably in the range from 300 μm to 400 μm.

The hollow microsphere content is generally in the range from 0.1% to60% by weight, preferably in the range from 5% to 50% by weight and morepreferably in the range from 10% to 30% by weight, the weight all beingbased on the total weight of hollow microspheres andmelamine-formaldehyde precondensate used for foam production.

The melamine-formaldehyde foams have an open-cell foam scaffoldcomprising a multiplicity of interconnected, three-dimensionallybranched struts (the points of connection between the struts being knownas “nodes” or “nodal points”). The hollow microsphere median particlediameter which is essential to the present invention and the hereinbelow described production process for the melamine-formaldehyde foamsof the present invention cause the hollow microspheres to becomepreferentially embedded into the open-cell pores of the foam structure.Incorporation into the struts or nodes of the foam scaffold does nottake place to any significant extent, if at all. As a result, goodfixation of the hollow microspheres in the foam is achieved even at highhollow microsphere contents without the mechanical properties of thefoam becoming excessively affected.

The melamine-formaldehyde foams of the present invention comprisinghollow microspheres are preferably obtainable by the consecutive processsteps a) and b):

-   -   a) heating to foam up and crosslink a mixture comprising a        melamine-formaldehyde precondensate having a molar ratio of        melamine:formaldehyde in the range of typically from 1:1.3 to        1:5 and preferably from 1:1.5 to 1:3.5, the hollow microspheres,        a curative, a dispersant and a blowing agent, and    -   b) drying the foam obtained in process step a),        wherein these process steps and also the melamine-formaldehyde        precondensates, curatives, dispersants and blowing agents useful        in step a) are known in principle to a person skilled in the art        and are described in the literature.

The melamine-formaldehyde precondensate in addition to melamine andformaldehyde may comprise up to 50% by weight and preferably up to 20%by weight (all based on the weight of cocondensed melamine) of otherthermoset-formers and up to 50% by weight and preferably up to 20% byweight (all based on the weight of cocondensed formaldehyde) of otheraldehydes in cocondensed form. Useful thermoset-formers include forexample: alkyl- and aryl-alkyl-substituted melamine, urea, urethanes,carboxamides, dicyandiamide, guanidine, sulfurylamide, sulfonamides,aliphatic amines, glycols, phenol and its derivatives. Examples ofuseful other aldehydes are acetaldehyde, trimethylolacetaldehyde,acrolein, benzaldehyde, furfurol, glyoxal, gluteraldehyde,phthalaldehyde and terephthalaldehyde. Particular preference is given toan unmodified melamine-formaldehyde precondensate, i.e., amelamine-formaldehyde precondensate devoid of any otherthermoset-formers or other aldehydes. Further details concerningmelamine-formaldehyde condensation products may be found in Houben-Weyl,Methoden der organischen Chemie, volume 14/2, 1963, pages 319 to 402.

Commercially available melamine-formaldehyde precondensates are usefulfor a multiplicity of fields of use, for example for further processinginto glues. Melamine-formaldehyde precondensates comprising sulfitegroups are advantageous for use in some of these fields. Such sulfitegroup-containing melamine-formaldehyde precondensates are obtainable forexample as described in EP-B 37470 whereby from 1% to 20% by weight ofsodium disulfite is incorporated in the course of the condensation ofmelamine and formaldehyde to obtain cocondensed sulfite groups. For theprocesses of the present invention, however, it is advantageous thatstep a) utilizes a precondensate which is free of the sulfite groups.

Emulsification of the blowing agent and stabilization of the foam instep a) requires the addition of a dispersant, e.g., an emulsifier oremulsifier mixture. Useful emulsifiers include anionic, cationic andnonionic surfactants and also mixtures thereof.

Suitable anionic surfactants are diphenylene oxide sulfonates, alkane-and alkylbenzenesulfonates, alkylnaphthalenesulfonates,olefinsulfonates, alkyl ether sulfonates, fatty alcohol sulfates, ethersulfates, alpha-sulfo fatty acid esters, acylaminoalkanesulfonates, acylisethionates, alkyl ether carboxylates, N-acylsarcosinates, alkyl andalkyl ether phosphates. Useful nonionic surfactants include alkylphenolpolyglycol ethers, fatty alcohol polyglycol ethers, fatty acidpolyglycol ethers, fatty acid alkanolamides, EO-PO block copolymers,amine oxides, glycerol fatty acid esters, sorbitan esters andalkylpolyglucosides. Useful cationic emulsifiers includealkyltriammonium salts, alkylbenzyldimethylammonium salts andalkylpyridinium salts. The emulsifiers are preferably added in amountsof 0.2% to 5% by weight, based on the melamine-formaldehydeprecondensate.

For the melamine-formaldehyde precondensate, which is preferably used inthe form of an aqueous solution or dispersion, to produce foam in stepa), it has to comprise a blowing agent, the amount depending on thedesired density of the foam. In principle, the process of the presentinvention can utilize both physical blowing agents and chemical blowingagents. Useful physical blowing agents include, for example,hydrocarbons, halogenated and more particularly fluorinatedhydrocarbons, alcohols, ethers, ketones and esters in liquid form or airand CO₂ as gases. Useful chemical blowing agents include, for example,isocyanates mixed with water, in which case CO₂ is released as aneffective blowing agent, moreover carbonates and bicarbonates mixed withacids, which likewise produce CO₂, and also azo compounds, such asazodicarbonamide. In one preferred embodiment of the present invention,the aqueous solution or dispersion of the melamine-formaldehydeprecondensate is admixed with between 1% and 40% by weight, based on themelamine-formaldehyde precondensate, of a physical blowing agent havinga boiling point of between 0 and 80° C.; in the case of pentane, theamount used is preferably in the range from 5% to 15% by weight.

Curatives used in step a) comprise acidic compounds catalyzing thecontinued condensation of the melamine-formaldehyde precondensate. Theamounts are between 0.01% and 20% by weight and preferably between 0.05%and 5% by weight, based on the melamine-formaldehyde precondensate.Organic and inorganic acids can be used, examples being hydrochloricacid, sulfuric acid, phosphoric acid, nitric acid, formic acid, aceticacid, oxalic acid, toluenesulfonic acids, amidosulfonic acids and alsoacid anhydrides.

The aqueous solution or dispersion of the melamine-formaldehydeprecondensate used in step a) is preferably free of further addedsubstances. However, it can be beneficial for some purposes to add up to20% by weight, and preferably less than 10% by weight, based on themelamine-formaldehyde precondensate, of customary added substances, suchas dyes, flame retardants, UV stabilizers, agents to lower combustiongas toxicity or to promote carbonization. Since the foams are generallyopen celled and capable of imbibing water, some applications make itnecessary to add hydrophobicizers in amounts of 0.2% to 5% by weight.Useful hydrophobicizers include for example silicones, paraffins,silicone surfactants, fluorosurfactants, hydrophobic hydrocarbonaceoussurfactants, silicone emulsions and fluorocarbon emulsions.

The concentration of the melamine-formaldehyde precondensate in themixture of precondensate and solvent/dispersant, more particularlywater, can vary within wide limits between 55% and 85% by weight andpreferably between 63% and 80% by weight, all based on the total weightof melamine-formaldehyde precondensate and solvent/dispersant. Thepreferred viscosity of the mixture of precondensate andsolvent/dispersant is between 1 and 3000 dPa·s and preferably between 5and 2000 dPa·s.

The hollow microspheres and further mixture components are mixed withthe aqueous solution or dispersion of the melamine-formaldehydeprecondensate to form a homogeneous mixture, with the blowing agentbeing forced in under pressure if necessary. However, it is alsopossible to start with a solid, for example spray-dried,melamine-formaldehyde precondensate and to subsequently mix it with adispersion of the hollow microspheres and/or with an aqueous solution ofthe emulsifier, with the curative and also with the blowing agent. Aftermixing, the heated resin mixture with the dispersed blowing agent isdischarged through a die and foams up thereafter.

Foaming of the blowing agent-containing solution or dispersion uponemergence from the die is augmented—as described in EP-B 17671—by meansof hot air or high frequency irradiation. Preferably, the energy can beinput by electromagnetic radiation, for example by high frequencyirradiation with 5 to 400 kW, preferably 5 to 200 kW, particularlypreferably 9 to 120 kW per one kilogram of the mixture used in afrequency range of 0.2 to 100 GHz, preferably 0.5 to 10 GHz. Magnetronsare a suitable source of radiation for dielectric radiation, with one ormore magnetrons being able to be irradiated at the same time.

The mixture to be foamed is irradiated immediately on emerging from thefoaming die. The blowing agent evaporates the resin mixture foams up andat the same time cures through.

The foams produced are finally dried to remove water and blowing agentremaining in the foam.

In a further embodiment of the process according to the presentinvention, process step b) may be followed by a process step c) in whichthe dried foam is press molded to make it elastic.

Process step c) is known in principle to a person skilled in the art andis described in the literature, for example in EP-A 1 505 105 and EP-B37470.

The foam blocks or sheets obtained can optionally be thermocompressed ina further process step. Thermocompression as such is known to a personskilled in the art and described for example in WO 2007/031944, EP-A 451535, EP-A 111 860 and U.S. Pat. No. 6,608,118. Thermocompression canoften provide better fixation of the hollow microspheres in the foamstructure.

Preferred hollow microspheres for producing the melamine-formaldehydefoams of the present invention have walls consisting of a polymer, aninorganic material or a combination of inorganic material and polymer(by adhering inorganic materials for example).

Polymers suitable for the hollow microsphere walls are preferablypolyurethane, melamine-formaldehyde resin, epoxy resin, polyester,polycarbonate, polyacrylates, polyamides or mixtures thereof.

Inorganic materials useful as hollow microsphere walls are preferablysilicates, particularly those of aluminum, of calcium, of magnesiumand/or of zirconium, oxides such as aluminum oxide, quartz, magnesite,mullite, chromite, zirconium oxide and/or titanium oxide, borides,carbides and nitrides such as silicon carbide, titanium carbide,titanium boride, boron nitride and/or boron carbide, carbon or glass andmore preferably glass.

The hollow microspheres are at least partly and more particularly fullyfilled with one or more solid or liquid benefit agent. Benefit agentsare for example a detergent compositions, hence are capable of improvingthe cleaning properties of the cleaning implement (1) based onmelamine-formaldehyde foams; or else surfactants; dyes, for example inksand pigments; scents; acids; bases; oils; salts; bleach; antimicrobialagents; fragrances; solvents; biocides, which are released bydestruction of the hollow microsphere walls to develop their benefit forthe particular desired use and mixtures thereof. Further usable benefitagents known per se to a person skilled in the art are for examplehydrophobicizing agents; agents influencing haptics or the soil releasebehavior (to obtain the so-called lotus effect for example);formaldehyde scavengers; abrasives such as inorganic nanoparticles forexample (see WO 2009/021963 for example) or synthetic abrasives; orcatalysts and mixtures thereof.

Preferred hollow microspheres comprising wall material based on a highlycross linked methacrylic ester polymer are known from EP-A-1 029 018,DE-A-101 39 171 and WO-A-2005/116559. They all relate tomicroencapsulated latent heat storage materials in different fields ofuse. EP-A-1 029 018 teaches the use in bindered building materials suchas concrete or gypsum, DE-A-101 39 171 teaches the use ofmicroencapsulated latent heat storage materials in gypsum board, andWO-A-2005/116559 teaches their use in chipboard. The hollow microspheresdescribed in these references all are said to have high imperviousnessin thermal treatment, chemical treatment and under pressure.

Hollow microspheres are obtainable via a so-called in situpolymerization for example. The basis for the principle of hollowmicrosphere formation is that the monomers, a free-radical initiator, aprotective colloid and the lipophilic substance to be encapsulated arecombined to form a stable oil-in-water emulsion. Then, thepolymerization of the monomers is started by heating and optionallycontrolled via further temperature elevation, the resulting polymersforming the hollow sphere wall which encloses the lipophilic substance.This general principle is described for example in DE-A-10 2007 055 813,WO2008071649 and DE-A-101 39 171, the content of which is herebyexpressly incorporated herein by reference.

DE-A-10 2007 055 813 describes the production and use of thermallydestructible hollow microspheres, which are likewise preferred. Thehollow microsphere wall is constructed of acrylates. The hollowmicrosphere interior contains lipophilic substances, such as aliphaticand aromatic hydrocarbon compounds, saturated or unsaturated C₆-C₃₀fatty acids, fatty alcohols, C₅-C₃₀ fatty amines, fatty acid esters,natural and synthetic waxes, halogenated hydrocarbons, silicone oils,adhesives, aroma chemicals, scents, active substances, dyes, colorformers, pigments and crosslinkers.

The weight ratio of hollow microsphere interior to hollow microspherewall, i.e., the core/wall ratio, is generally in the range from 50:50 to95:5, preferably in the range from 70:30 to 95:5 and more preferably inthe range from 75:25 to 93:7.

The melamine-formaldehyde foams obtained according to the presentinvention generally have a density in the range from 3 to 100 g/l andmore preferably have a density in the range from 5 to 50 g/l.

The present invention melamine-formaldehyde foams comprising hollowmicrospheres are obtainable batchwise or preferably continuously assheets or webs in generally any desired thickness, advantageously inlayer thicknesses ranging from 0.1 to 500 cm, preferably from 0.5 to 200cm, more preferably from 1 to 100 cm, more particularly from 3 to 80 cmand most preferably from 5 to 50 cm. Moldings comprisingmelamine-formaldehyde foams according to the present invention areobtainable in a continuous manner and preferably in a batchwise manner.

The melamine-formaldehyde foams in the form of webs, sheets, moldings orsome other form can be laminated or endowed with surface layers bygenerally customary methods on one, two, more or all sides, for examplewith paper, paperboard, glass overlay matt, wood, plasterboard, metalsheet or metal foil, plastic or self-supporting plastics foam/sheet,which may optionally also be foamed. The surface layers can be appliedin the course of foaming or subsequently. In the case of subsequentapplication, it is advantageous to use an adhesion promoter.

When the melamine-formaldehyde foams of the present invention comprisehollow microspheres filled with benefit agent to be released, thisrelease can be affected at any desired time by applying a suitablemechanical or thermal action to the foam. For example, theabove-described benefit agents, for example detergent compositions,surfactants, inks, scents or biocides, acids, bases, bleaches, water,solvents, waxes, pigments, dyes, fragrances, oils, salts and mixturesthereof, can be released through thermal (e.g., hot air, various formsof radiation, for example infrared or microwave radiation) or mechanicaldestruction (pressing, rolling, ultrasound, etc) of the hollowmicrosphere walls. This releases the contents of the hollow microspheresuniformly or almost uniformly and causes wetting of the surfacestructure (struts and nodes) even in the interior of the open-cellmelamine-formaldehyde foam structure. The processes for thermal ormechanical destruction of microcapsule walls are known in principle to aperson skilled in the art, and are described in the literature. Forexample, the foam can be compression molded to destroy the microcapsulewalls, as described in EP-A 0451535 for example, by leading the foamthrough a defined gap between two contra-rotating rolls in parallelalignment. In addition to leading the foam through a gap between twoco-rotating rolls, it is also possible for the foam to be transported ona conveyor belt and for a roll—turning at the same circumferential speedas the speed of movement of the foam—to press down on the foam. Thepressure on the foam can further be exerted by placing the foam forexample into a press in which a ram presses down on the foam. In thiscase, however, continuous pressing is not possible.

The cleaning implement based on melamine-formaldehyde foams comprisinghollow microspheres are used for cleaning hard surfaces.

The melamine-formaldehyde foams of the present invention exhibit moreparticularly even at high loadings, i.e., hollow microsphere contentsand optionally associated benefit agent contents, good mechanicalproperties for the foam and better fixing of the hollow microspheres inthe foam. Furthermore, the hollow microspheres can be incorporated inthe foam in the course of foam production without additional processstep.

Packaging Means

The cleaning implement herein may be combined in an article ofmanufacture with a packaging means.

The packaging means herein may be any suitable means known to packagecleaning implements. Indeed, particularly suitable packaging meansherein are selected from the group consisting of: paper bags, plasticbags, cartons, carton boxes, flow wraps, plastic wraps, and paper wraps,and the like and combinations thereof.

The packaging means herein may be printed and/or modified. Inparticular, such printing and/or other modification may be used toassociate a brand-name and/or logo of a hard surface cleaner with saidcleaning implement.

Method of Cleaning a Hard Surface

In another embodiment the present invention encompasses method ofcleaning a hard surface with a cleaning implement as described hereinabove.

In yet another embodiment herein, the present invention encompasses amethod of cleaning a hard surface by bringing a cleaning implementaccording to the present invention into contact with said hard surface.By “cleaning” it is meant herein removing spots and/or stains from hardsurfaces.

In still another embodiment herein, the present invention encompasses amethod of cleaning a hard surface with cleaning implement according tothe present invention.

Suitable hard surfaces herein are tiles, walls, floors, sanitaryfittings such as sinks, showers, shower curtains, wash basins, WCs,household appliances including, but not limited to, refrigerators,freezers, washing machines, automatic dryers, ovens, microwave ovens,dishwashers and so on.

The methods of cleaning a hard surface according to the presentinvention may additionally include the step of wetting said cleaningimplement or said foam with an appropriate solvent, preferably tapwater, more preferably water in combination with a detergentcomposition, prior to bringing said cleaning implement into contact withsaid hard surface.

EXAMPLES Methods of Measurement Mechanical Properties, Elasticity

Ram pressure measurements for evaluating the mechanical quality of themelamine resin foams were all carried out as described in U.S. Pat. No.4,666,948. A cylindrical ram having a diameter of 8 mm and a height of10 cm was pressed into a cylindrical sample having a diameter of 11 cmand a height of 5 cm in the direction of foaming at an angle of 90°until the sample tore. The tearing force [N], hereinafter also referredto as ram pressure value, provides information as to the quality of thefoam.

Comparative Example V-1

Producing melamine-formaldehyde foam without hollow microspheres(according to WO-A-2009/021963):

75 parts by weight of a spray-dried melamine-formaldehyde precondensate(molar ratio 1:3) were dissolved in 25 parts by weight of water, then 3%by weight of formic acid, 2% by weight of a sodium C₁₂/C₁₄-alkylsulfate, 38% by weight of pentane, all % by weight being based on theweight of the precondensate, were added, this was followed by stirringand then foaming in a polypropylene mold (for foaming) by irradiationwith microwave energy. After foaming, the foam was dried for 30 minutes.

This melamine-formaldehyde foam had a density of 7.5 g/l and a rampressure value of 18.9 N.

Inventive Example 4 and Comparative Examples V-2, V-3 and V-5

In each case, 75 parts by weight of a spray-dried melamine-formaldehydeprecondensate (molar ratio melamine:formaldehyde 1:3) were dissolved in25 parts by weight of water. This mixture was admixed with 3 parts byweight of formic acid, 2 parts by weight of a fatty alcohol polyglycolether as surfactant, 38 parts by weight of pentane and 10% by weight(based on the total weight of the melamine-formaldehyde precondensate)of hollow glass microspheres based on soda-lime silicate glass havingthe mean particle diameters (D₅₀, volume averaged, Malvern, Fraunhoferdiffraction) and bulk densities mentioned in table 1. This mixture wasvigorously stirred and then foamed in a polypropylene foaming mold byirradiation with microwave energy at 2.54 GHz. The foams formed in eachcase were subsequently dried with hot air.

The properties of the melamine-formaldehyde foams obtained in each caseare reported in table 1.

TABLE 1 amount and size of hollow microspheres and properties ofmelamine-formaldehyde foams Example V-1 V-2 V-3 4 V-5 Hollowmicrosphere, amount — 10 10 10 10 [% by weight] Hollow microsphere,median particle — 50 190 360 650 diameter (D₅₀, volume averaged,Malvern, Fraunhofer diffraction) [μm] Bulk density [g/l] — 32 26 20 16Properties Density [g/l] 7.5 7.5 7.9 7.5 6.9 Ram pressure [N] 18.9 11.214.6 18.5 15.1

Use of Melamine-Formaldehyde Foam Comprising Hollow Microspheres asCleaning Implements or to Clean Hard Surfaces.

Cleaning Implement A

A single layer cleaning implement having a cuboid shape defined by threegroups of parallel and equal length sides, referred to as a, b and c,with a being 6.5 cm, b being 12 cm, and c being 3 cm is cut from thefoam according to present invention. The overall shape of CleaningImplement A is similar to the cleaning implement of FIG. 1. Cleaningimplement A comprising hollow microspheres comprising benefit agent.

Cleaning Implement A is used to clean hard surfaces. Indeed, CleaningImplement A is wetted with water and thereafter brought into contactwith the hard surface to be cleaned. Cleaning Implement A shows anexcellent performance in removing greasy soap scum and neat kitchen dirtfrom said hard surface whilst providing adequate surface safety.

Cleaning Implement B

A dual layer cleaning implement having a cuboid shape defined by threegroups of parallel and equal length sides, referred to as a, b and c,with a being 6.5 cm, b being 12 cm, and c being 4 cm is made by foamflame laminating a first layer of the foam according to presentinvention, having a thickness—side c—of 2 cm to a second layer ofcommercially available polyurethane foam, having a thickness—side c—of 1cm. The two layers are joined together at the plane formed by sides aand b. The overall shape of Cleaning Implement B is similar to thecleaning implement of FIG. 2. Cleaning implement B comprising hollowmicrospheres comprising benefit agent.

Cleaning Implement B is used to clean hard surfaces. Indeed, CleaningImplement B is wetted with water and thereafter the foam according topresent invention side of Cleaning Implement B is brought into contactwith the hard surface to be cleaned by rubbing said side over the areato be cleaned. The excessive amount of water is thereafter absorbed bythe polyurethane layer of Cleaning Implement B by swiping the cleanedsurface with said layer. Cleaning Implement B shows an excellentperformance in removing greasy soap scum and neat kitchen dirt from saidhard surface whilst providing adequate surface safety.

Cleaning Implement C

A dual layer cleaning implement having a cuboid shape defined by threegroups of parallel and equal length sides, referred to as a, b and c,with a being 6.5 cm, b being 12.5 cm, and c being 2.5 cm is made by apermanent adhesive a first layer of hybrid foam according to presentinvention, having a thickness—side c—of 2 cm to a second layer ofcommercially available polyurethane foam, having a thickness—side c—of0.5 cm. The two layers are joined together at the plane formed by sidesa and b. The overall shape of Cleaning Implement C is similar to thecleaning implement of FIG. 2. Cleaning implement C comprising hollowmicrospheres comprising benefit agent.

Cleaning Implement C is used to clean hard surfaces. Indeed, CleaningImplement C is wetted with water and thereafter the foam according topresent invention side of Cleaning Implement C is brought into contactwith the hard surface to be cleaned by rubbing said side over the areato be cleaned. The excessive amount of water is thereafter absorbed bythe polyurethane layer of Cleaning Implement C by swiping the cleanedsurface with said layer. Cleaning Implement C shows an excellentperformance in removing greasy soap scum and neat kitchen dirt from saidhard surface whilst providing adequate surface safety.

Use of Melamine Formaldehyde Foam Comprising Hollow MicrospheresAccording to Present Invention to Clean a Hard Surface

A piece of melamine-formaldehyde foam comprising hollow microspheresaccording to present invention is used to clean a hard surface bywetting a piece of said foam with water and thereafter bringing it intocontact with the hard surface to be cleaned. The foam according thepresent invention shows an excellent performance in removing greasy soapscum and neat kitchen dirt from said hard surface, whilst providingsurface safety.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A cleaning implement based onmelamine-formaldehyde foam comprising hollow microspheres, wherein saidhollow microspheres have a median particle diameter (D50, volumeaveraged, Malvern, Fraunhofer diffraction) in the range from 260 μm to490 μm, and wherein the hollow microsphere are at least partly filledwith a benefit agent.
 2. The cleaning implement according to claim 1,wherein the hollow microsphere content is in the range from 0.1% to 60%by weight, wherein the percentages by weight are based on the totalweight of hollow microspheres and melamine-formaldehyde precondensateused for foam production.
 3. The cleaning implement according to claim2, wherein the melamine-formaldehyde foam comprises open-cell pores andthe hollow microspheres are embedded into the open-cell pores of thefoam structure.
 4. The cleaning implement according to claim 3, whereinthe hollow microsphere walls consist of a polymer or of an inorganicmaterial.
 5. The cleaning implement according to claim 4, wherein thehollow microsphere walls consist of glass.
 6. The cleaning implementaccording to claim 5, wherein benefit agent is selected from the groupconsisting of a detergent composition; surfactants; dyes; inks;pigments; scents; acids; bases; oils; salts; bleach; antimicrobialagents; fragrances; solvents; biocides; hydrophobicizing agents; agentsinfluencing haptics; agents influencing the soil release behavior;formaldehyde scavengers; abrasives such as inorganic nanoparticles;synthetic abrasives; or catalysts and mixtures thereof.
 7. A method ofcleaning a hard surface comprising the steps of: a) providing a cleaningimplement based on melamine-formaldehyde foam comprising the hollowmicrospheres according to claim 1; and b) rubbing the cleaning implementagainst a surface.